发表机构
Korea Astronomy and Space Science Institute; University of Science and Technology; Inter-University Centre for Astronomy and Astrophysics; Bogolyubov Institute for Theoretical Physics（韩国天体物理与空间科学研究所; 科学技术大学; 大学间天文与天体物理中心; 博戈留波夫理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在最小幻影膜上提出亚稳态暗能量模型，通过衰变与膜屏蔽的相互作用实现幻影分界线穿越，与DESI观测一致，优于ΛCDM。
AI 中文摘要
近期DESI观测暗示对动力学暗能量的偏好，其状态方程（EoS）在$w=-1$处穿越幻影分界线。在本工作中，我们研究最小幻影膜上的\textit{亚稳态}暗能量（DE）。膜世界效应导致早期$w < -1$，而DE的亚稳态衰变导致晚期$w > -1$。我们考虑幻影膜上的三种亚稳态衰变方案：指数衰减的DE组分（M1）、DE衰变为非重子暗物质（M2）以及衰变为暗辐射（M3）。利用CMB观测、DESI DR2 BAO测量和DES-Dovekie Ia型超新星样本，我们将这些模型与$\Lambda$CDM、Chevallier--Polarski--Linder（CPL）参数化以及具有非衰变$\Lambda$的最小幻影膜模型进行比较。我们发现膜上的亚稳态模型优于$\Lambda$CDM，其衰变率分别为M1、M2和M3的$\Gamma/H_0=0.362\pm0.086$、$0.539\pm0.125$和$0.483\pm0.112$。亚稳态模型的最佳拟合相比$\Lambda$CDM改善$\Delta\chi^2_{\rm MAP}=-17.14$、$-18.76$和$-18.22$，而相应的$\Delta{\rm DIC}$值为$-8.66$、$-9.63$和$-6.56$。膜世界屏蔽在$z\gtrsim0.4$时驱动有效幻影行为，而DE衰变在接近当前纪元时将EoS推向非幻影值，幻影分界线$w=-1$在$z \simeq 0.3$--$0.4$处被穿越。这些结果表明，亚稳态衰变与幻影膜屏蔽之间的相互作用为有效穿越幻影分界线提供了一种简单的物理机制，与DESI观测一致。
英文摘要
Recent DESI observations hint at a preference for dynamical dark energy with an equation of state (EoS) that crosses the phantom divide at $w=-1$. In this work, we investigate \textit{metastable} dark energy (DE) on the minimal phantom brane. Braneworld effects lead to $w < -1$ at early times, whereas metastable decay of DE results in $w > -1$ at late times. We consider three metastable decay prescriptions on the phantom brane: an exponentially decaying DE component (M1), decay of DE into non-baryonic dark matter (M2), and decay into dark radiation (M3). Using CMB observations, DESI DR2 BAO measurements, and the DES-Dovekie Type Ia supernova sample, we compare these models with $Λ$CDM, the Chevallier--Polarski--Linder (CPL) parametrization, and the minimal phantom-brane model with a non-decaying $Λ$. We find that metastable models on the brane are preferred over $Λ$CDM, their decay rates being $Γ/H_0=0.362\pm0.086$, $0.539\pm0.125$, and $0.483\pm0.112$ for M1, M2, and M3, respectively. Best fits of metastable models improve over $Λ$CDM by $Δχ^2_{\rm MAP}=-17.14$, $-18.76$, and $-18.22$, while the corresponding $Δ{\rm DIC}$ values are $-8.66$, $-9.63$, and $-6.56$. Braneworld screening drives effective phantom behaviour at $z\gtrsim0.4$, while DE decay drives the EoS toward non-phantom values closer to the present epoch, with the phantom divide $w=-1$ being crossed at $z \simeq 0.3$--$0.4$. These results show that the interplay between metastable decay and phantom-brane screening provides a simple physical mechanism for an effective crossing of the phantom divide consistent with DESI observations.
Comments11 pages, 7 figures. Comments are welcome
